On Tue, 2012-10-23 at 03:02 -0700, Shreyas Bhatewara wrote:
Please dont top post on netdev or lkml
> Well, actually the driver does split large frags into frags of
> VMXNET3_MAX_TX_BUF_SIZE bytes each.
>
> vmxnet3_drv.c
> 711 while (len) {
> 712 u32 buf_size;
> 713
> 714 if (len < VMXNET3_MAX_TX_BUF_SIZE) {
> 715 buf_size = len;
> 716 dw2 |= len;
> 717 } else {
> 718 buf_size = VMXNET3_MAX_TX_BUF_SIZE;
> 719 /* spec says that for TxDesc.len, 0 == 2^14 */
> 720 }
> 721
> ....
> 743
> 744 len -= buf_size;
> 745 buf_offset += buf_size;
> 746 }
Only the skb head is handled in the code you copy/pasted.
You need to generalize that to code in lines ~754
Then, the number of estimated descriptors is bad :
/* conservatively estimate # of descriptors to use */
count = VMXNET3_TXD_NEEDED(skb_headlen(skb)) +
skb_shinfo(skb)->nr_frags + 1;
Yes, you need a more precise estimation and vmxnet3_map_pkt() should
eventually split too big frags.
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